In fuel injection systems of the port injection or throttle body type, it is common to provide fuel pressure regulators which function by having a fuel pump to supply fuel to the regulator at an inlet to cause a diaphragm assembly to move away from a valve seat to control the fuel flow through the outlet of the regulator and to the tank. Pressure is maintained at the desired pressure differential between the pump and the outlet of the regulator. The fuel pump displaces a fixed flow rate so the amount of fuel returned to the tank varies with engine speed, the largest return rate occurring at idle. When the fuel pump is stopped the regulator starts to close then acts as a shut off valve to maintain pressure on the system.
In one common type of regulator as shown in U.S. Pat. No. 3,511,270, the valve comprises a small ball attached to a plate which allows for angular misalignments of the diaphragm assembly to the valve seat. In that arrangement, accurate complementary flat surfaces must be provided on both the ball and the plate. In U.S. Pat. No. 4,237,924, a spherical ball having a flat portion is seated in a socket member which is yieldingly urged by a diaphragm to bring the flat portion against an annular valve seat. Accurate flat surfaces are also required in such an arrangement.
Among the objects of the present invention are to provide a fuel pressure regulator which obviates the need for accurate formation of flat surfaces and the like and which can be manufactured at low cost.
The fuel pressure regulator embodying the invention comprises a housing, a diaphragm dividing the housing into a first chamber and second chamber, a passage from the exterior of the housing to the first chamber, an inlet and an outlet associated with the second chamber of the housing, and a valve seat associated with the outlet. A cage is mounted on and movable with the diaphragm and a spring within the first chamber yieldingly urges the cage toward the valve seat. The cage supports a pair of plates which retain a valve ball. The first plate has an opening through which a portion of the ball projects and a second plate retains the first plate and ball within the cage. The first plate is movable laterally to provide for proper centering of the ball in the valve seat. A light spring extends between the cage and the ball to urge the ball against the first plate.